Best sealant for a roof pipe penetration
Finding a sealant that properly adheres to existing materials like tar and shingles is the main hurdle when re-sealing an insulated and re-clad pipe. Because no one onsite will share clear best practices and video tutorials are unreliable, contractors are left paranoid about leaving small gaps around the new fittings.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Using Henry 209XR sealantDid this help you?
- 2Filling the void, building a pitch pan, and filling with pourable sealerDid this help you?
- 3Using a storm collar to counter flash the pipeDid this help you?
- 4Sealing the installed boot with a rubber collarDid this help you?
- 5Applying roofing sealant or tar underneath the jackDid this help you?
- 6Using a no leak flashing with a rubber grommet insteadDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“I left the bottom of the pipe fitting open and there’s a small gap. It’s my first time, you can see where I replaced the shingles. I used nails and tar to secure the shingles and pipe fitting.”source ↗
“I am currently working on replacing the cooling tower feed line which includes removing all galv piping and replacing with copper tubing.”source ↗
“the work was bid to include re-sealing the penetration once i have insulated and re-clad the piping, and I want to do it right.”source ↗
“no one onsite is willing to give a straight answer on best practice.”source ↗
“i am paranoid and determined to get a sealant which will properly adhere to the existing material.”source ↗
“Can you send a link? Youtube can also be my enemy”source ↗
Where this came up
People with this problem also raised
- 10Gap around furnace b-vent after roofing
- 30HVAC lineset leaking through the roof
- 3How to fill gaps in roof edges to keep pests out
- 6How to install drip edge on an existing roof
- 19How to temporarily waterproof a damaged roof until replacement
- 3How to connect a second story gutter to a first story gutter cleanly